Plourde G, et al. - Characterization was pursued of the effect of dexmedetomidine, a selective adrenergic α-2 agonist with lesser hypnotic potency, on the gamma (30–80 Hz) and high-gamma (80–200 Hz) thalamocortical EEG rhythms. The intent was to inspect the proposition that the attenuation of these rhythms by isoflurane and propofol was a correlate of anaesthetic action. It was determined that dexmedetomidine attenuated high-frequency thalamocortical rhythms, but to a lesser degree than isoflurane and propofol. The primary variations between dexmedetomidine and the other anaesthetics encompassed the thalamic rhythms. This illustrated the tie-up between impaired thalamic function and anaesthesia. Increased delta coherence possibly represented the cyclic hyperpolarization of thalamocortical networks. It could serve as a marker for loss of consciousness.